Cooling system for electric discharge devices



Oct. 2, 1934. o. SEITZ COOLING SYSTEM FOR ELECTRIC DISCHARGE DEVICES Filed Aug. 28, 1933 Patented Oct. 2, 1934 COOLING SYSTEM FOR ELECTRIC DISCHARGE DEVICES Oskar Seitz, Baden,

Aktiengesellschaft Bro Switzerland, assignor to wn Boverl & Cie., Baden,

Switzerland, a joint-stock company of Switzerland Application August 28, 1933, Serial No. 687,161 In Germany August 20, 1932 12 Claims.

This invention relates to improvements in cooling systems utilizing the circulation of a cooling fluid, and more particularly to the cooling of apparatus such as electron discharge devices which operate in the most satisfactory manner when maintained within predetermined limits of temperature.

In high output electron discharge devices generally, and more particularly in devices utilizing a vaporizable material as the vehicle for the discharge, it is necessary to provide a flow of cooling fluid along the walls of the device to remove the heat liberated in the discharge and to maintain the space within the device within the most advantageous temperature limits. If fresh water is utilized as cooling fluid, the consumption of such water is considerable at high outputs of the device and the points of the device at which the cooling v.aid enters are generally cooled too intensely. Such disadvantages are avoided by the use of indirect cooling, but the necessary equipment then becomes expensive and requires additional maintenance.

By means of a cooling system utilizing fresh water and providing a partial forced recirculation of the heated water, the result is obtained that the water enters the cooling passages of the device at more suitable temperatures and that the consumption of fresh water is considerably reduced and may even be interrupted when the load of the device is low. The flow of water is preferably rendered more uniform under varying conditions by inserting a reservoir in the cooling circuit. When the installation is shut down, the reservoir receives the fluid contained in the cooling passages of the device and maintains such fluid at a suitable temperature.

It is, accordingly, one of the objects of the present invention to provide a cooling system for a fluid cooled device in which the flow of cooling fluid is partially recirculated.

Another object of the present invention is to provide a cooling system for a fluid cooled device in which the flow of cooling fluid is quickly regulated in response to the changes of load of the device.

Another object of the present invention 18 to provide a cooling system for a fluid cooled device in which the flow of cooling fluid enters the cooling passages of the device at a temperature aoove the temperature oithe fluid received from the source.

Another object of the present invention is to provide a cooling system for a fluid cooled device in which the flow of cooling fluid-leaves the cooling passages of the device at a temperature below a predetermined limit.

Another object of the present invention is to provide a cooling system for a fluid cooled device in which the flow of cooling fluid is forced through the cooling passages of the device by means of a pump.

I Another object of the present invention is to provide a cooling system for electron discharge devices in which the flow of cooling fluid is controlled by the means controlling the energization of the device.

Another object of the present invention is to provide a cooling system for electron discharge devices in which the flow of cooling fluid is controlled by means responsive to the temperature of the device. v

Another object of the present invention is to provide a cooling system for electron discharge devices in which the flow of cooling fluid may be supplied from a source at low pressure.

Another object of the present invention is to provide a cooling system for electron discharge devices in which a quantity of cooling fluid is stored at a predetermined temperature when the device is out of operation.

Objects and advantages other than those above described will be apparent from the following description when read in connection with the accompanying drawing, which diagrammatically illustrates one embodiment of the present invention applied to the cooling of an electron discharge device operable as an alternating current rectifier.

Referring more particularly to the drawing by characters of reference, reference numeral 1 designates an alternating current line herein represented as a three phase line, from which current is to be drawn and supplied in rectified form to a direct current line having a negative conductor 2 and a positive conductor 3. The line 1 is connected by means of a circuit breaker 4 with the primary winding 6 of a transformer having a secondary winding '7. Winding 7 comprises a plurality of winding portions severally connected with the anodes 8 of an electron discharge device 9 and connected to form a neutral point connected with conductor 2. Device 9 may be of any suitable type known in the art and is herein represented as being ofthe mercury cathode type having the cathode thereof connected with conductor 3, and will hereinafter be referred to as rectifier 9 for the sake of brevity. Line 1 also supplies current to an auxiliary transformer 11 serving the purpose of supplying current for neutral point of the secondary winding thereof at an intermediate point of a resistor 14 connected between conductors 2 and 3. Rectifier 9 is provided with any necessary discharge initiating and maintaining means, such means being well known and, therefore, 'not shown. Rectifier 9 is also provided with suitable passages 16 for the flow of cooling fiuid which is preferably fresh water obtained from any suitable supply (not shown) through an inlet pipe 17. The circuit for the flow of fresh water from pipe 17 comprises a closing valve 18, a solenoid operated valve 19, a thermostatically operated valve 21, a hand operated valve 22, suitable pumping means such as a pump 23 driven by a suitable motor 24, valves 26 and 27, and an insulating portion 28 of suitable insulating material such as a length of rubber hose. The

water issuing from the outlet of the rectifier cooling passages is conducted through a pipe 30 wherefrom such water drops into a funnel 31, such interruption in the circuit providing the necessary insulation between the rectifier and ground on the outlet side and permitting a visual indication of the flow of the water. The funnel 31 conducts the water into a chamber 32 containing a thermostat bulb 35 controlling valve 21, to a valve 33 and to a reservoir 34 located entireLv below the level of the lowest point of the cooling passages of rectifier 9. A portion of the water overflows from reservoir 34 through pipe 36 to a drain, the remainder of the water being returned to pump 23 through a non-retum valve 37. A

. valve 38 is also inserted in a connection between position, relay valves 21 and 27. Valve 21 is by-passed by an ad-- justable valve 39. Water may also be conducted from chamber 32 directly to the drain by means of a' valve 41.

Circuit breaker 4 is provided with a closing coil which may be energized from transformer 11 through a switch 42. In theclosed position thereof, circuit breaker 4 bridges auxiliary contacts 43 which are connected in parallel with contacts 44 of a thermostat 46 responsive .to the temperature of the. cooling water in one of passages 16. Contacts 43 and 44 control the energization of the coil of a relay 47. When in the energized 47 bridges contacts 48, thereby energizing the solenoid of valve 19 and also energizing motor 24 through a switch 49. In the deenergized condition, relay 47 closes contacts 51, thereby energizing the coil of a time relay 52 controlling the operation of a-solenoid valve 53 inserted between reservoir 34 and pump 23 to bypass valve 37. Reservoir 34, is provided with a level gage 54 and with a drain valve 56. To

Qmaintain the water within reservoir 34 at a uni- I form temperature, the walls of the reservoir are covered with thermal insulation 57. The water also heated by a heater 53 controlled by a thermostat 59 connecting such heater with transformer 11 when the temperature of the water falls below a predetermined limit.

In normal operatio valves 18, 22, 26, 27' and 33 are open and valves 38, 39, 41 and 56 are closed. Switch 49 is closed to connect motor 24 in parallel with the solenoid of valve 19. Line 1 being energized, closure of switch 42 causes circuit breaker 4 to be closed, thereby initiating operation of rectifier 9. Contacts 43 connect the coil of relay 47 with transformer 11 and relay 47 closes contacts 48, thereby energizing motor 24 and the solenoid of valve 19. If the temperature of bulb 35 is low, such bulb will maintain valve 21 closed. Upon starting of motor 24, pump 23 driven by such motor causes any water present in reservoir 34 and in passages 16 to flow from pump 23 through valves 26 and 27, pipe 28, passages 16, pipe 30, funnel 31, chamber 32, valve 33, reservoir 34 and non-return valve 37. Continued operation of rectifier 9 causes thermostat 46 to close contacts 44 which then remain closed in parallel with contacts 43. Thermostatv 35 causes valve 21 to gradually open and a flow of fresh water then occurs from pipe 17 through valves 18, 19, 21 and 22, pump 23 through the circuit already described above to reservoir 34. A portion of such water then flows to the drain through pipe 36 and the remainder is recirculated by pump 23 through the circuit above described. During such operation, non-return valve 37 prevents the flow of water from pipe 17 through valves 18, 19, 21, 22 and reservoir 34 to the drain. The pressure of the water supplied through pipe 17 may be'lower than is generally required in a fresh water cooling system as the flow of water through the system is insured by the action of pump 23. The amount of fresh water flowing through the system is controlled by valve 21 and thermostat 35 in a manner such as to maintain the temperature of the water leaving the cooling passages of the rectifier at a substantially uniform value not exceeding a predetermined limitl The temperature of the water entering the rectifier through pipe 28 is intermediate between the temperature of the water leaving the rectifier and the temperature of the fresh water, but may reach the temperature of the water leaving the rectifier when valve 21 is closed. When rectifier 9 is put out of operation by opening of circuit breaker 4, the flow of water through the rectifier will be maintained by pump 23 as long as thermostat 46 maintains contacts 44 closed and thereby maintains motor 24 and solenoid of valve 19 in energized condition. When contacts 44 open in response-to the decrease of thet'emperature of rectifier '9, relay 47 opens contacts 48, thereby causing the flowof water through rectifier 9 to cease. Contacts 51 of relay 47 are then closed, thereby causing energization of the coil of time delay relay 52. After a predetermined time delay, relay 52 closes the contacts thereof, thereby energizing the solenoid, of

valve 53. The water then present in the cooling passages 16 of rectifier 9 returns to reservoir 34, any amount of water in excess of the capacity of the reservoir flowing to the drain through pipe 36. The thermal insulation of the reservoir prevents rapid cooling of the water contained therein and such water is maintained above a predetermined temperature by means of heater 58 '4 and thermostat 59. Cooling passages 16"being then empty, the air contained therein serves as thermal insulation to-prevent too rapid cooling. of the walls of rectifier 9. When the rectifier is again put into operation, the walls thereof will therefore be at a higher temperature than if the cooling passages thereof had been maintained full of water and much higher than if a flow of fresh water therethrough had been permitted to continue. Upon starting of pump 23, the warm water of reservoir 34 is immediately pumped into passages 16. If, for any reason, it is desired to utilize fresh water cooling, valves 18, 27, 38 and 41 are opened .curring on the walls of the passages.

and valves 22, 26, 33 and 56 are closed. Switch 49 is opened to disconnect motor 24 from transformer 11 even when relay 47 is closed. The flow I of water then occurs through valves 18, 19, 21,

38 and 27 and pipe 28, passages 16, pipe 30, funnel 31, thermostat chamber 32 and valve 41 to the drain. A small flow of water is caused to occur through valve 39. The purpose of such flow of water is to cause water heated in passages 16 to reach thermostat 32 and cause opening of valve 21 when such valve is entirely closed as in case the rectifier is put in operation after a protracted period of inoperation.

When it is desired to disconnect rectifier 9 from the cooling system for repairs or for any other reason, valve 2'7 is closed. If it is desired to drain reservoir 34, the water contained therein is released by means of valve 56.

It may be seen that the above system provides simple and inexpensive cooling means for a rectifier providing the sensitiveness and narrow temperature range characteristic of the recooling systems while avoiding the expense and additional maintenance of the usual recoolers. The outlet temperature of the water is maintained substantially uniform at small loads as well as at high loads by means of thermostat 35 and valve 21, thereby constantly maintaining the rectifier at the most advantageous operating temperature. No point of the rectifier is cooled to an undesirably low temperature by the inlet of fresh water and the most satisfactory operating conditions of the rectifier are insured. The results of such conditions are operation at a low arc drop, the absence of surges and of backfires in the rectifier, and a satisfactory operation of the control electrodes which is diflicult to obtain when the temperature of the rectifier is not properly controlled. When the load on the rectifier is low, the heat generated in the discharge is dissipated by radiation and convection alone and no fresh water need be consumed. In the present system the flow of water through passages 16 is caused to occur at a greater velocity than would be necessary with fresh water cooling with the result that sludge does not accumulate in the passages and air pockets do not form therein, thereby reducing the amount of corrosion oc- The system responds rapidly to changes of load of the rectifier by means of thermostat 35 and being thus sensitively controlled, gives an accurate regulation of the temperature. The fresh water supply may be a low pressure source which might possibly be useless in the absence of recirculating pump 23.

Although but one embodiment of the present invention has been described and illustrated, itwill be apparent to those skilled in the art that various changes and modifications may bemade therein without departing from the spirit of the invention or from the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

1. In combination with a device to be cooled and provided with passages for the flow of cooling fluid therethrough, a source of cooling fluid for said device, pumping means having an inlet connected with said source and causing circulation of cooling fluid therefrom through said passages, means for automatically causing operation of said pumping means when the device is put in operatiomand means for returning a portion of the fluid to the inlet of said pumping means.

2. In combination with a device to be cooled and provided with passage: for the flowof cooling fluid therethrough, a source of cooling fluid for said device, pumping means having an inlet connected with said source and causing circulation of cooling flpid therefrom through said passages, means for automaticaJly causing operation of said pumping means in response to the temperature of the fluid in one of said passages, and means for returning a portion of the fluid to the inlet of said pumping means.

3. In combination with a device to be cooled and provided with passages for the flow of cooling fluid therethrough, a source of cooling fluid for said device, pumping means having an inlet connected with said source and causing circulation of cooling fluid therefrom through said passages, means for returning a portion of the fluid to the inlet of said pumping means, and means for interrupting the supply of fluid from said source and for interrupting the action of said pumping means upon shutdown of said device and for preventing subsequent cooling thereof below a predetermined temperature.

4. In combination with a device to be cooled and provided with passages for the flow of cooling fluid therethrough, a source of cooling fluid for said device, pumping means having an inlet connected with said source and causing circula-. tion of cooling fluid therefrom through said passages, storage means having an overflow and receiving the fluid circulated through said passages, means for returning a portion of the fluid to the inlet ofsaid pumping means, and means for causing delayed draining of 'said passages into said storage means during inoperative periods of said device.

5. In combination with a device to be cooled and provided with passages for the flow of cooling fluid therethrough, a source of cooling fluid for said device, pumping means having an inlet connected with said source and causing circulation of cooling fluid therefrom through said passages, means for returning a portion of the fluid to the inlet of said pumping means, and means responsive to the 120 temperature of the fluid from said passages to control the supply of fluid from said source to said pumping means.

6. In combination with a device to be cooled and provided with passages for the flow of cooling fluid 125 therethrough, a source of cooling fluid for said device, pumping means having an inlet connected with said source and causing circulation of cooling fluid therefrom through said passages, means for returning a portion of the fluid to the inlet 130 of said pumping means, storage means having an overflow and receiving the fluid circulated through said passages, means for causing delayed draining of said passages into said storage means during inoperative periods of said device, and 5 means for maintaining the fluid within said storage means above a predetermined temperature.

7. In combination with a device to be cooled and provided with passages for the flow of cooling fluid therethrough, a source of cooling fluid for said 140 device, pumping means having an inlet connected with said source and causing circulation of cooling fluid therefrom through said passages, storage means having an overflow and receiving the fluid circulated through said passages, means for returning a portion of the fluid to the inlet of said pumping means, and means for disconnecting said pumping means from said source and for directly connecting said source with said passages. 150

8. In combination with a device to be cooled and provided with passages for the flow of cool ing fluid therethrough, a source of cooling fluid for said .device, pumping means havingan inlet connected with said source and causing circulation of cooling fluid therefrom through said passages, means for returning a portion of the fluid to the inlet of said pumping means, and means responsive to the temperature of the fluid issuing from said passages to control the supply of fluid from said source to said pumping means, and a by-pass permitting a constant flow of fluidin addition to the variable flow of fluid through the last said means. 7

9. In combination with a device having passages for the flow of cooling media therethrough, of a source of cooling medium, means operable to cause theflow of said medium continuously supplied thereto from said source through said passages, and means for returning to the first said means a portion only of said medium, after discharge thereof from said passages, to said meansfor recirculation thereby through said passages.

10. In combination with a device having passages for the flow of cooling media therethrough;

of a source of cooling medium, means operable to cause the-flow of said medium continuously supplied thereto from said source through said passages, storage means for receivingsaid medium after discharge thereof from said passages, and

means for returning a portion only of said medium from said storage means to the .first said means for recirculation thereby through said passages.

11. In combination with a device having passages for the flow of cooling media therethrough, of a source of cooling medium, means operable to cause the flow of said medium continuously supplied thereto through said passages, means for returning a portion only of said medium,after' discharge thereof from said passages, to said, means for recirculation thereby through said pasof said medium, after discharge thereof fromsaid passages, to said means for recirculation thereby through said passages at temperatures greater than the temperature of the medium supplied from said source.

OSKAR SEITZ. 

